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Old 08-04-2011 | 10:08 AM
  #478  
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MantisWorx
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Originally Posted by Cautrell05
There are some very smart people posting in this thread and alot of good info being shared. It is however painfully aparent in the last couple of pages that several of you have no idea of how to properly scale a car. The solid rod idea is a waste of time and completley unneeded if you scale it right. Sorry if I hurt your feelings but it had to be said.

First off, dont bother- I repeat, DO NOT BOTHER looking at individual corner weights untill last. Period. If your balancing a car you look at pairs. Always.

when adjusting the spring collars there are a few rules.

Rule 1 - You can't shift total weight between axles, LF + RF = Constant

Rule 2 - You can't shift total weight between sides, LF + LR = Constant

Rule 3 - You CAN shift total weight between diagonal measures, LF + RR /= Constant

Rule 4 - Adjusting any one wheel weight will change all wheel weights

Quoted from here- http://www.elephantracing.com/techto...nerbalance.htm

Scale the car as its going to be raced. Simple enough. Yes friction from the shocks will afffect corner weights but will not affect left or rear weight.

To do it right is simple. First you take all 4 of your corner weights and total them. Write that down. then take your left front and left rear weights and total them. Then take that total and divide it by the total vehicle weight. That is your left side percentage. Ideal for anything other than oval is 50%. Then take your left rear and right rear and total them. Divide that total by your total weight and you have the rear percentage. That will vary depending on the car, track conditions and driver preference. Worry about seperate wheel weights later
For example-

1500 gram buggy.
Lf 250g RF 275G
LR 500G RR 475G

Left side total 250+500 750G. 750 divided into 1500 total, 0.5 which is 50%
Left rear + right rear 975G. Divide that into the 1500 total is o.65 which is 65%.
Those are the first two things you look at before you worry about individual corner weights.
The only way to change those percents is to move weight. lead, battery esc and so on.

Lets say you crank on the collars and come up with this
LF 212 RF 313
LR 538 RR 427

Ovbiously corner weights are way off. If you check the percents however-
Left 212+538= 750. 750/1500=50%
Rear 538+427=975. 975/1500=65%
They are still the same. Where you place or move weight will affect rear and lefr/right at the same time. You have to look at the whole picture when making adjustments and it will go easier.

After you get the desired rear weight and your left/right set where you want then its time to look at corner weights. Keep in mind that if your not 50/50 left/right you will not get both sides even. by that I mean you might get the fronts even but the rears will be heavier on one side. Only way to get the fronts and rears matched side to side is to be 50/50. personally I would try to get the rear tires as even as possible. If one rear tire is heavier it will turn easier one way than the other. it will be more consistent if they are even.
Also check your shocks before you start. make sure they are the same length and have the same amount of rebound. If you know they are even before you start then theres no need to take it apart after you get it set and do it again.

Nick
VERY good information and i am not arguing that point, my argument is the inconsistency of oil filled shocks and the tendency for them to change. what you are missing is that fact that what happens if for some reason you MUST add weight (ROAR spec etc etc)where do you put the weight? Your technique is the proper way of doing it . but as we all know if a fly lands on one of your shock towers ALL of your readings will be off. the point of me making these solid shocks is just to WEIGHT BALANCE the chassis and nothing more, i realize that even after performing this act the shock collars will still need to be adjusted but if i am at 100% balance with no shocks, put the shocks on(with exact collar settings) and it is all over the place dont you agree that there is something amiss. having to turn a collar 2 turns to correct something that was perfect with them tells me that on that shock something is not right, be it stiction, rebound, bad spring etc etc
Fred has alot of experience with road racing so dont underestimate his opinions as im pretty sure he can balance a car, instead of quoting from someone elses information he has his own experience in 1:1 as do I. there are more than one way to skin a cat and i can find articles counteracting everything you said although i agree with the technique.

you and i both know that it is not easy to get the EXACT amount of rebound in all four shocks no matter how good you are. so much that i no longer even try! zero rebound in all of them and use RCshox for accurate rebound!




may work, may not but will know as i am playing with them right now!
let me also add this, since we are adjusting RC cars we have the luxury of putting weight virtually anywhere we want but in a real car you cant so therefore some things are not the same with scaling RC cars.......
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